The additivity tests between seven monoclonal antibodies to Shanghai Isolate of Ribgrass Mosaic Virus were determined by ELISA method. Adding two non-labeling monoclonal antibodies to the same well coated by virus antigen separately, the amount of bound antibodies were measured and compared with that of bound each monoclonal antibody.The additivities of reactions between monoclonal antibodies 1H2 and 12H3 and between 7H1 and 10H1, 11H2,17H6, 29H1 were found.However no additivities of reactions were found be...